1. Field of the Invention
The present invention relates to a magnetic recording medium and a method of manufacturing a magnetic recording medium.
2. Description of the Related Art
Conventionally, magnetic recording media such as a hard disc have magnetic layer which is sectioned into a plurality of data areas and a plurality of servo areas for information recording. Servo information intended for control such as head positioning is magnetically recorded on the servo areas in a predetermined servo pattern.
The process of recording the servo information has a problem of low productivity since servo pattern parts of the servo areas and the peripheral parts thereof are magnetized in opposite polarities one by one for every magnetic recording medium by a servo track writing method. In particular, with a recent improvement in surface recording density and an accompanying decrease in head flying height, high-density high-precision recording has also been required of the servo information. This means an increasing need for an improvement to the recording efficiency of the servo information.
In view of this, there have been proposed magnetic recording media in which the magnetic layer is formed only in either ones of the servo pattern parts and the peripheral parts so that a servo pattern is formed physically (for example, see Japanese Patent Laid-Open Publication No. H 6-195907). In this case, a direct-current magnetic field can be uniformly applied to the magnetic recording medium to magnetize the magnetic layer to the servo pattern, with a significant improvement in the recording efficiency of the servo information.
Recently, much attention has been given to magnetic recording media of discrete type in which the magnetic layer in the data areas is separated into a number of recording elements for the sake of a significant increase in surface recording density. Such a magnetic recording medium of discrete type is advantageous in that the magnetic layer can be separated and processed in the data areas simultaneously with in the servo areas.
Nevertheless, if servo patterns are made of recesses and projections, the airflow between the magnetic recording medium and the head is disturbed to make the flying height and orientation of the head unstable, causing the problem of a drop in information recording/read accuracy.
In particular, many servo patterns have certain regularities, which can often contribute to unstable airflow between the magnetic recording medium and the head. Servo patterns are determined depending on disc drives on the head side, and it is therefore impossible to adopt arbitrary servo patterns for stabilizing the airflow between the magnetic recording medium and the head.
In addition, the pattern of the recesses and projections at the surface vary largely across the boundaries between the servo areas and the data areas. Consequently, the head flying height and the head orientation tend to be unstable across the boundaries between the servo areas and the data areas in particular.